Methods, systems, and computer readable media for performing diameter answer message-based network management at a diameter signaling router (DSR)

ABSTRACT

Methods, systems, and computer readable media for performing Diameter answer message-based network management at a Diameter signaling router (DSR) are disclosed. According to one method, a Diameter answer message that includes error indicator information is received from a first Diameter node at a DSR. The error indicator information included in the Diameter answer message is examined, at the DSR, and information based on the error indicator information is used to update status information for routes maintained by the DSR to the first Diameter node.

PRIORITY CLAIM

This application claims the benefit of U.S. Provisional PatentApplication Ser. No. 61/304,310 filed Feb. 12, 2010; the disclosure ofwhich is incorporated herein by reference in its entirety.

STATEMENT OF INCORPORATION BY REFERENCE

The disclosures of each of the following commonly-owned, co-pending U.S.patent applications filed on Feb. 11, 2011 are hereby incorporatedherein by reference in their entireties:

-   -   “Methods, Systems, And Computer Readable Media for        Inter-Diameter-Message Processor Routing,” (Ser. No.        13/025,968);    -   “Methods, Systems, And Computer Readable Media For Source Peer        Capacity-Based Diameter Load Sharing” (Ser. No. 13/026,031);    -   “Methods, Systems, And Computer Readable Media For Inter-Message        Processor Status Sharing,” (Ser. No. 13/026,105);    -   “Methods, Systems, And Computer Readable Media For Providing        Priority Routing At A Diameter Node,” (Ser. No. 13/026,060);    -   “Methods, Systems, And Computer Readable Media For Providing        Peer Routing At A Diameter Node,” (Ser. No. 13/026,076);    -   “Methods, Systems, And Computer Readable Media For Providing        Origin Routing At A Diameter Node,” (Ser. No. 13/026,081);    -   “Methods, Systems, And Computer Readable Media For Providing        Local Application Routing At A Diameter Node,” (Ser. No.        13/026,098);    -   “Methods, Systems, And Computer Readable Media For Answer-Based        Routing Of Diameter Request Messages,” (Ser. No. 13/026,112);    -   “Methods, Systems, And Computer Readable Media For        Multi-Interface Monitoring And Correlation Of Diameter Signaling        Information,” (Ser. No. 13/026,133);    -   “Methods, Systems, And Computer Readable Media For Diameter        Protocol Harmonization,” (Ser. No. 13/026,144);    -   “Methods, Systems, And Computer Readable Media For Diameter        Network Management,” (Ser. No. 13/026,153); and    -   “Methods, Systems, And Computer Readable Media For Diameter        Application Loop Prevention,” (Ser. No. 13/026,162).

TECHNICAL FIELD

The subject matter described herein relates to processing of Diameteranswer messages. More specifically, the subject matter relates tomethods, systems, and computer readable media for performing Diameteranswer message-based network management at a Diameter message routingagent, such as a Diameter signaling router (DSR) node.

BACKGROUND

Diameter is an authentication, authorization and accounting (AAA)protocol for computer networks, and is a successor to RADIUS. TheDiameter base protocol is defined in IETF RFC 3588, the disclosure ofwhich is incorporated herein by reference herein in its entirety.Diameter communications may use a request-answer message exchange.Conventional Diameter answer message processing, including conventionalrelaying and proxying of answer messages, may be performed by a Diametermessage routing agent. The base Diameter specification requires thatanswer message responses be routed over the same network path as thecorresponding request message was forwarded. When a Diameter agentreceives an answer message, it must route the message to the peer fromwhich it received the corresponding request message. In order to ensurethat each answer message is returned along the same path as itscorresponding request message, the Diameter routing agent may maintainrouting state information for each pending Diameter transaction (i.e., aDiameter request awaiting an answer).

As such, a Diameter routing agent is typically deployed in such a mannerso as to permit the Diameter routing agent to see both the request andanswer message portions of a Diameter transaction. However, theprocessing of answer messages is limited to their specific transactions,even though the answer messages may contain information that is usablefor network management purposes. Accordingly, in light of thesedifficulties, a need exists for improved methods, systems, and computerreadable media for improved network management in Diameter networks.

SUMMARY

Methods, systems, and computer readable media for performing Diameteranswer message-based network management at a DSR are disclosed.According to one method, a Diameter answer message that includes errorindicator information is received from a first Diameter node at a DSR.The error indicator information included in the Diameter answer messageis examined, at the DSR, and the error indicator information is used toupdate status information for routes maintained by the DSR to the firstDiameter node.

A system for performing Diameter answer message-based network managementis also disclosed. The system includes a Diameter signaling router(DSR). The DSR includes a Diameter message processor for receiving aDiameter answer message that includes error indicator information from afirst Diameter node. A network management (NM) module examines the errorindicator information contained in the Diameter answer message and usesthe error indicator information to update status information for routesmaintained by the DSR to the first Diameter node.

According to another aspect, a method for providing network managementis disclosed. The method includes establishing a lost answer messagetimer signifying a time period, after which, if an answer messageresponsive to a Diameter request message has not been received, it isdetermined that the answer message is lost. In response to determiningthat an answer message is lost, network management informationmaintained at the DSR may be updated and potentially distributed toother interested Diameter peer nodes. Additionally, resources may bedeallocated by the DSR, which may include removing one or more pendingtransaction records maintained by the DSR.

According to another aspect, a system for unsolicited network managementcommunication is disclosed. The system includes a DSR. The DSR includesa network management module for establishing a lost answer message timersignifying a time period, after which, if an answer message responsiveto a Diameter request has not been received, it is determined that theanswer message is lost and for updating Diameter network managementinformation associated with a Diameter request message in response todetermining that no Diameter answer message related to a Diameterrequest message was detected prior to expiration of the lost answermessage timer. The system further includes a Diameter message processorfor communicating Diameter network management information associatedwith a Diameter request message to one or more Diameter nodes in thenetwork.

The subject matter described herein can be implemented in software incombination with hardware and/or firmware. For example, the subjectmatter described herein can be implemented in software executed by aprocessor. In one exemplary implementation, the subject matter describedherein can be implemented using a non-transitory computer readablemedium having stored thereon executable instructions that when executedby the processor of a computer control the processor to perform steps.Exemplary non-transitory computer readable media suitable forimplementing the subject matter described herein include chip memorydevices or disk memory devices accessible by a processor, programmablelogic devices, and application specific integrated circuits. Inaddition, a computer readable medium that implements the subject matterdescribed herein may be located on a single computing platform or may bedistributed across plural computing platforms.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter described herein will now be explained with referenceto the accompanying drawings of which:

FIG. 1A is a block diagram of an exemplary Diameter signaling router forperforming Diameter answer message-based network management according toan embodiment of the subject matter described herein;

FIG. 1B is a block diagram of a Diameter signaling router having adistributed internal architecture according to an embodiment of thesubject matter described herein;

FIG. 2 is a flow chart illustrating exemplary steps for updating statusinformation for routes based on error indicator information contained ina Diameter message as part of performing Diameter answer message-basednetwork management at a DSR according to an embodiment of the subjectmatter described herein;

FIG. 3 is a message sequence diagram illustrating an exemplary broadcastscenario as part of performing Diameter answer message-based networkmanagement at a DSR according to an embodiment of the subject matterdescribed herein;

FIG. 4 is a flow chart illustrating exemplary steps for caching Diameterinformation and responding on behalf of another Diameter node as part ofperforming Diameter answer message-based network management at a DSRaccording to an embodiment of the subject matter described herein;

FIG. 5 is a message sequence diagram illustrating an exemplaryconditional-on-Response “error” condition proxy scenario as part ofperforming Diameter answer message-based network management at a DSRaccording to an embodiment of the subject matter described herein;

FIG. 6 is a message sequence diagram illustrating an exemplaryconditional-on-absence of Response condition proxy scenario as part ofperforming Diameter answer message-based network management at a DSRaccording to an embodiment of the subject matter described herein; and

FIGS. 7A and 7B are diagrams illustrating an exemplary answer-basedinternal status sharing scenario as part of performing Diameter answermessage-based network management at a DSR according to an embodiment ofthe subject matter described herein.

DETAILED DESCRIPTION

As mentioned above, a Diameter routing agent is typically deployed insuch a manner so as to permit the Diameter routing agent to see both therequest and answer message portions of a Diameter transaction.Accordingly, the subject matter described herein includes methods,systems, and computer readable media for exploiting this particularcharacteristic of Diameter message routing/propagation through aDiameter network in order to obtain and share Diameter networkstatus/network management information among interested Diameter entitiesin the network.

FIG. 1A is a block diagram of an exemplary Diameter relay/signalingrouting node for performing Diameter answer message-based networkmanagement according to embodiments of the subject matter describedherein. Referring to FIG. 1A, Diameter signaling router (DSR) 100 mayinclude a Diameter connection layer (DCL), Diameter routing layer (DRL),one or more applications, and one or more routing tables. DSR 100 mayperform a variety of Diameter message routing functions and, therefore,may include functionality of a Diameter routing agent, Diameter relayagent, Diameter redirect agent, Diameter proxy agent, and/or Diametertranslation agent. Exemplary DRL capabilities may include: routingrequest messages to peers or local applications based on messagecontent, discarding or rejecting Diameter request messages based onmessage content rules, peer congestion control, allowing an operator toaccess only the features and capacities that are purchased, and easierconfiguration. In addition to message routing, DSR 100 may support avariety of value-add services/applications. In order to support bothapplication processing and core Diameter routing functions, DSR 100 maysupport two message routing tables: an application routing table (ART)and a peer routing table (PRT). Additionally, the subject matterdescribed herein for performing Diameter answer message-based networkmanagement may be designed with the assumption that answer messagesand/or request messages will be lost and, therefore, effectively handlelost answer messages in order to avoid wasting memory or other resourcesto maintain pending transaction records for transactions that are nolonger pending.

Diameter message processor 101 may be a printed circuit board includingthe processor and associated memory for performing Diameter routing andanswer based message processing as described herein. As such, Diametermessage processor 101 may support a variety of layers and applicationsby performing these functions. One layer on Diameter message processor101 is Diameter application layer (DAL) 102.

DAL 102 may include applications 104. Exemplary applications 104 mayinclude, but are not limited to, a Diameter client, Diameter server,translation agent, proxy agent, redirect agent, and a load generator.DAL 102 may also include timer 106 and application data 108. DAL 102 mayinterface with Diameter message encode/decode library 110 for encodingand decoding Diameter messages.

Common platform services 112 may include buffer services 114, databaseservices 116, measurements events alarms and logs (MEAL) services 118,and high availability (HA) services 120.

Diameter message processor 101 may further include Diameter routinglayer (DRL) 124. DRL 124 may be responsible for the following functions.DRL 124 may perform ingress and egress message looping detection andprevention. DRL 124 may route ingress message to one or more local DSRapplications based upon user-define rules. DRL 124 may reroute messagesupon failures. DRL 124 may perform message routing based upon routepriorities and weights. DRL 124 may perform message routing based uponuser-defined message content. DRL 124 may perform message routing topeers with multiple transport connections. DRL 124 may manage peertransport connections (TPS). DRL 124 may throttle ingress messages basedupon local DSR congestion. DRL 124 may detect and avoid peer congestion.DRL 124 may load balance peer connection load to meet MP TPSconstraints.

DRL 124 may include answer-based request routing module 126, eventprocessing module 128, DRL rerouting module 130, answer routing module132, routing data 134, and DRL timer task 136. Answer-based requestrouting module 126 may route request messages based on informationdetermined from previously received answer messages. The functionalityof routing answer messages based on request messages is described indetail in the above-described commonly-assigned patent applicationentitled, “Methods, Systems, and Computer Readable Media forAnswer-Based Routing of Diameter Request Messages.” Message processor101 may further include Diameter network management module 137 forupdating route data 134 based on information learned from answermessages. The functionality of network management module 137 will bedescribed in further detail below.

DRL 124 may communicate with DAL 102 via message-based APIs. Forexample, DRL 124 may use application indication and application requestAPIs to communicate with DAL 102.

Diameter connection layer (DCL) 138 may perform the following functions.DCL 138 may implement Diameter connection state machine 140 for eachDiameter peer. DCL 138 may establish transport connections with Diameterpeers and process Diameter peer-to-peer messages and relatedfunctionality. This may include capabilities exchange request/answer(CER/CEA), Diameter Watchdog request/answer (DWR/DWA), and DisconnectPeer request/answer (DPR/DPA). DCL 138 may interface with the DRL 124 bysending Diameter messages received from peers to DRL 124 using one ormore message-based APIs. DCL 138 may send Diameter messages receivedfrom DRL 124 to the appropriate peer. DCL 138 may notify DRL of peertransport connection and congestion status changes. DCL 138 may processconfiguration and maintenance requests from DSR OAM for transportconfiguration objects. DCL 138 may update MEAL data for transportconfiguration objects. DCL 138 may perform transport layer capacitycontrol.

DCL 138 may include Diameter message dispatch module 140, DCL listenermodule 142, DCL timer task 144, and connection data 145.

DCL 138 may also include one or more IP transport tasks. For example,DCL 138 may include IP transport task 146 and 148, where each IPtransport task includes a receiving thread and a transmitting thread.For example, IP transport task 146 includes Rx thread 150 and Tx thread152 and IP transport task 148 includes Rx thread 154 and Tx thread 156.IP transport tasks 146 and 148 may each communicate with SCTP/TCPsockets for interfacing with an operating system. For example, IPtransport task 146 may communicate with SCTP/TCP socket 158 and IPtransport task 148 may communicate with SCTP/TCP socket 160. SCTP/TCPsockets 158 and 160 may be associated with OS 162.

For simplicity, DSR 100 illustrated in FIG. 1A includes a single messageprocessor 101. This is one possible configuration of DSR 100, where asingle message processor routes all Diameter signaling messages.However, DSR 100 may include full message processors, each configured asmessage processor 101 illustrated in FIG. 1A. FIG. 1B illustrates suchan embodiment. In FIG. 1B, DSR 100 includes a plurality of messageprocessors 101A-D, each of which sends Diameter signaling messages toand receives Diameter signaling messages from a Diameter network.Message processors 101A-D may be connected through an internal network162. Although each message processor 101A-D may include all of thecomponents of message processor 101 illustrated in FIG. 1A, forsimplicity, only network management modules 137 and routing data 134 areillustrated in FIG. 1B. In operation, when a Diameter message arrives atone of message processors 101A-D, the message is routed based onDiameter signaling information and the message from the ingress messageprocessor to the egress message processor, and from the egress messageprocessor to the Diameter network. As will be described in detail below,each Diameter message processor 101A-D may perform the steps describedherein for answer-based network management, which may be used to updaterouting or status information maintained by each message processor.

FIG. 2 is a flow chart illustrating exemplary steps for providingnetwork management in a communications network that includes a Diameterrelay/signaling routing node according to an embodiment of the subjectmatter described herein. Referring to FIG. 2, in step 200, a Diameteranswer message sent by a first Diameter node may be received at a DSRelement that maintains Diameter route and route status information forrouting Diameter messages to nodes in a Diameter network, where theDiameter answer message includes error indicator information.

In step 202, the error indicator information contained in the Diametermessage may be examined. For example, the error indicator informationmay include error Diameter_Too_Busy or any other error indicatorsspecified in the Diameter base protocol.

In step 204, the error indicator information may be used to updatestatus information for routes to the first Diameter node. For example,network management module 137 may update routing data 134 based onstatus information from a received answer message.

FIG. 3 is a message flow diagram illustrating an exemplary messagesequence for providing network management in a communications networkthat includes a Diameter routing agent/translation agent/proxyagent/relay agent/redirect agent/signaling routing node according to anembodiment of the subject matter described herein. Referring to FIG. 3,DSR 100 and associated answer-based network management module 137 maycommunicate with Diameter peer node 300. Diameter peer node 302 andDiameter node 304. For example, Diameter peer node 300 may send Diameterrequest message 306 to DSR 100. DSR 100 may forward Diameter requestmessage 308 to Diameter node 304. In response, Diameter node 304 mayreturn Diameter response message 310 that includes error indicatorinformation to DSR 100. At step 312, DSR 100 may analyze Diameter answermessage 310 and its error indicator information and generate a networkmanagement message. DSR 100 may then send Diameter answer message 314including the error indicator information to Diameter peer node 300 andDiameter network management message 316 to Diameter peer 302. Diameternetwork management message 316 may, for example, include an error causecode and the identity of the affected Diameter node (e.g., the fullyqualified domain name for Diameter node 304).

FIG. 4 is a flow chart illustrating exemplary steps for providinganswer-based network management according to an embodiment of thesubject matter described herein. Referring to FIG. 4, in step 400, afirst Diameter answer message sent by a first Diameter node is receivedat a DSR node, where the first Diameter answer message includes errorindicator information. For example, DSR 100 may receive an answermessage from a Diameter server node.

In step 402, information that identifies the affected Diameter node (oran application subsystem associated with the affected Diameter node) andassociated error indicator information is cached based on the firstDiameter answer message. For example, DSR 100 may cache information fromthe answer message that identifies an affected subsystem of the Diameterserver.

In step 404, a first Diameter request message sent by a second Diameternode is received at the DSR node, where the first Diameter requestmessage is destined for the first Diameter node. For example, a Diameterclient may send a request message to DSR 100, where the request isdestined for the Diameter server.

In step 406, a second Diameter answer message is generated on behalf ofthe first Diameter node, where the second Diameter answer messageincludes information that is based on at least a portion of the errorindicator information. For example, DSR 100 may use the cachedinformation to generate an answer message on behalf of the server.

In step 408, the second Diameter answer message is communicated to thesecond Diameter node. For example, DSR 100 may send the generated answerto the client that originated the request.

FIG. 5 is a message sequence diagram illustrating an exemplary messagesequence for providing network management in a communications networkthat includes a Diameter relay/signaling routing node according to anembodiment of the subject matter described herein. Referring to FIG. 5,Diameter peer node 300 may send Diameter request message 500 to DSR 100.DSR 100 may forward Diameter request message 502 to Diameter node 304.In response, Diameter node 304 may return Diameter answer message 504that includes error indicator information to DSR 100. At step 506, DSR100 may analyze Diameter answer message 504 and its error indicatorinformation. DSR 100 may then send Diameter answer message 508 includingthe error indicator information or information that is based at least inpart on the error indicator information to Diameter peer node 300. DSR100 may also send Diameter request message 510 and Diameter answermessage 512 including the error information or information that is basedat least in part on the error indicator information to Diameter peernode 302.

FIG. 6 is a message sequence diagram illustrating an exemplary messagesequence for providing network management in a communications networkthat includes a Diameter relay/signaling routing node according to anembodiment of the subject matter described herein. Referring to FIG. 6,Diameter peer node 300 may send Diameter request message 600 to DSR 100.DSR 100 may route Diameter request message 602 to Diameter node 304. Atstep 604, DSR 100 may start a timer for awaiting an answer to Diameterrequest message 602. At step 606, the response timer may expire withoutreceiving a Diameter response message to Diameter request message 602.At step 608, status information associated with Diameter node 304 may beupdated. Additionally, at step 608, upon receipt of a next Diameterrequest message destined for Diameter node 304, DSR 100 may proxy aDiameter response message including error indicator information onbehalf of Diameter node 304. DSR 100 may then send Diameter requestmessage 610 and Diameter response message including the error indicatorinformation to Diameter peer node 302.

In an alternate embodiment, DSR 100 may start a timer when a Diameterrequest message is routed to or towards a destination and subsequentlydetect the expiration of this timer. If a Diameter answer message,related to the previously routed Diameter request message, is notdetected prior to the expiration of the timer, then DSR 100 may beadapted to update internal route or destination status informationassociated with the Diameter request message. DSR 100 may furthercommunicate associated Diameter network management/status informationassociated with the route or destination of the Diameter request messageto one or more Diameter nodes in the network. For example, DSR 100 maycommunicate a network management message to a Diameter node in thenetwork, where the network management message includes information whichindicates that the route or destination associated with the Diameterrequest message is experiencing problems (e.g., congested, unavailable,unreachable, is not responding, etc.). Such unsolicited networkmanagement notifications may be made to other Diameter nodes (e.g.,Diameter routing agents, Diameter application servers, etc.) that havebeen either statically or dynamically provisioned. A staticallyprovisioned list/table/database of subscribing and subscribed-toDiameter nodes may be pre-provisioned at DSR 100. A dynamicallyprovisioned list/table/database of subscribing and subscribed-toDiameter nodes may be constructed in real-time at DSR 100 as each“interested” Diameter node signals the router with informationidentifying those Diameter nodes to which it would like to subscribe tonetwork management information updates. Such network managementsubscription information may be maintained, for example, at DSR 100 by aprocess or module associated with DRL 124 or DAL 102.

Answer-Based Internal Status Sharing

FIGS. 7A and 7B are diagrams illustrating an exemplary answer-basedinternal status sharing scenario as part of performing Diameter answermessage-based network management at a DSR according to an embodiment ofthe subject matter described herein. Referring to FIG. 7A, DSR logicalnetwork element 700 may include multiple virtual Diameter relay nodes702, 704, 706, and 708. Each virtual Diameter relay node 702-708 may beassociated with a peer routing table (PRT) and application routing table(ART) 710, 712, 714, and 716, respectively. DSR logical network element700 may be a DSR, such as DSR 100, where each MP functions as a virtualDiameter relay node. As such, network management information learned byone virtual relay node based on a received answer message may bedirected to other relay nodes within NE 700.

ARTs 710-716 may each contain a prioritized list of user-configurablerouting rules which define which local applications to invoke, and inwhich order, based upon message content.

PRTs 710-716 may each contain a prioritized list of user-configurablerouting rules which define where to route a message to a peer based uponmessage content.

Diameter peer node 718 may send Diameter request message 720 to virtualDiameter relay node 702. Virtual Diameter relay node 702 may then directDiameter request message 722 to egress virtual Diameter relay node 708.Virtual Diameter relay node 708 may then start a response/answer timerand route Diameter request message 726 to Diameter peer node 728.

Referring to FIG. 7B, at step 730, the response/answer timer may expirebefore virtual Diameter relay node 708 receives Diameter responsemessage 732 associated with Diameter request message 726. It isappreciated that Diameter response message 732 may include internalstatus update information for Diameter peer node 728.

Virtual Diameter relay node 708 may then communicate status updateinformation to some or all virtual Diameter relay nodes in the DSR. Forexample, virtual Diameter relay node 708 may communicate status updates734A, 734B, and 734C to virtual Diameter relay nodes 706, 702, and 704,respectively. In response, virtual Diameter relay nodes 706, 702, and704 may update their respective ARTs and PRTs 714, 710, and 712,respectively, with the status information provided in status updates734A, 734B, and 734C.

Lost Answer Responses

When answer messages are lost prior to their receipt by DSR 100, the“pending transactions” associated with the lost answer messages shouldeither be aborted (answer response sent to peer) or re-routed. Since DSR100 cannot directly “detect” a lost answer message, nor can it query theremote status of a forwarded Request message, it may predict with highprobability that one has been lost.

One such prediction method may be time-based. If an answer has not beenreceived in “X” seconds, then the answer message may be assumed to mostlikely be lost. The larger the value of “X”, the higher the probabilityof loss. In one embodiment, a DRL “Lost answer Timer” may be supportedand operator-configurable. An exemplary default value for X may be 30seconds. It may be appreciated that the value of X may also beapplication dependent. For example, if the “Lost answer Timer” isapplication specific and DSR 100 supports multiple applications, thevalue may be per-application specific. It may also be appreciated thatwhen the “Lost answer Timer” expires, DRL 124 may abort the transaction(default) and send an answer Response message. In another embodiment,DRL 124 may re-route the transaction.

Processing Answer Responses from Redirect Agents

It may be appreciated that the process for redirecting a responsemessage may be a DRL-configurable option.

According to one embodiment, the response message may be propagatedbackwards. This may be a default option.

According to another embodiment, the response message may be re-routedusing Redirect-Host AVPs.

Routing Answer Responses to Unavailable/Congested Peers

When DRL 124 receives an answer message and the message cannot beimmediately delivered because the transport layer queue for the peer isfull or the peer is congested, then DRL 124 has two options: delaydelivery of the message within DRL 124 or immediately discard the answermessage.

Delaying delivery of the message within DRL 124 may include bufferinganswer messages for a configurable time-period X1. If the peer's statuschanges before the timer expires, then the buffered answer messages maybe forwarded. If the timer expires and the peer is Available, then anattempt may be made to forward the buffered answer message until thebuffer is flushed or another blocking condition occurs (e.g., transportqueue full). In order to prevent an answer message from being queuedindefinitely, a “maximum answer message queue delay” may be supported(i.e., message aging) where the answer message may be discarded when theabove mentioned maximum delay is exceeded. It may be appreciated that ifthe transport connection is blocked for an inordinate period of time,preventing any answer messages from being sent, the transport layer maybe disconnected in order to clear the condition and trigger the peer tore-forward the messages in the pending transaction queue(s).

It will be understood that various details of the subject matterdescribed herein may be changed without departing from the scope of thesubject matter described herein. Furthermore, the foregoing descriptionis for the purpose of illustration only, and not for the purpose oflimitation, as the subject matter described herein is defined by theclaims as set forth hereinafter.

What is claimed is:
 1. A method for providing answer message-basednetwork management, the method comprising: receiving, at a Diametersignaling router (DSR), a first Diameter answer message from a firstDiameter node, wherein the first Diameter answer message includes errorindicator information, wherein the first Diameter answer message istransmitted by the first Diameter node in response to a requesttransmitted to the first Diameter node and wherein the error indicatorinformation concerns status of the first Diameter node; examining, atthe DSR, the error indicator information included in the first Diameteranswer message; and using the error indicator information to updatestatus information for routes maintained by the DSR to the firstDiameter node.
 2. The method of claim 1 comprising generating, by theDSR, a network management message based on the error indicatorinformation received from the first Diameter node and communicating thenetwork management message to other Diameter nodes.
 3. The method ofclaim 1 wherein using the error indication information to update thestatus information includes updating status information maintained byeach of a plurality of message processors of the DSR.
 4. A method forproviding answer message-based network management, the methodcomprising: receiving, at a Diameter signaling router (DSR), a firstDiameter answer message from a first Diameter node, wherein the firstDiameter answer message includes error indicator information; examining,at the DSR, the error indicator information included in the firstDiameter answer message; and using the error indicator information toupdate status information for routes maintained by the DSR to the firstDiameter node, wherein the error indicator information indicates thatthe first answer message cannot be immediately delivered to a peerbecause a transport layer queue for the peer is full or congested. 5.The method of claim 4 comprising buffering the first answer message fora configurable time period X1.
 6. The method of claim 5 comprisingforwarding the buffered answer message to the peer if the peer's statuschanges before the configurable time period X1 expires.
 7. The method ofclaim 5 comprising attempting to forward the buffered answer message, ifthe configurable time period X1 expires and the peer's status isavailable, until the buffer is flushed or another blocking conditionoccurs.
 8. The method of claim 5 comprising discarding the first answermessage once the time period X1 expires.
 9. A method for providinganswer message-based network management, the method comprising:receiving, at a Diameter signaling router (DSR), a first Diameter answermessage from a first Diameter node, wherein the first Diameter answermessage includes error indicator information; examining, at the DSR, theerror indicator information included in the first Diameter answermessage; using the error indicator information to update statusinformation for routes maintained by the DSR to the first Diameter node;receiving, the DSR, a first Diameter request message sent by a secondDiameter node, wherein the first Diameter request message is destinedfor the first Diameter node; in response to receiving the first Diameterrequest message, generating a second Diameter answer message on behalfof the first Diameter node, wherein the second Diameter answer messageincludes information based on at least a portion of the error indicatorinformation included in the first Diameter answer message; andcommunicating the second answer message to the second Diameter node. 10.The method of claim 9 wherein the error indicator information identifiesan affected application subsystem associated with a Diameter node.
 11. Asystem for providing answer message-based network management, the systemcomprising: a Diameter signaling router including: a Diameter messageprocessor associated for receiving a first Diameter answer message froma first Diameter node, wherein the first Diameter answer messageincludes error indicator information, wherein the first Diameter answermessage is transmitted by the first Diameter node in response to arequest transmitted to the first Diameter node and wherein the errorindicator information concerns status of the first Diameter node; and anetwork management (NM) module for examining the error indicatorinformation contained in the first Diameter answer message and using theerror indicator information to update status information for routesmaintained by the DSR to the first Diameter node.
 12. The system ofclaim 11 wherein the Diameter message processor is configured togenerate a network management message based on the error indicatorinformation received from the first Diameter node and to communicate thenetwork management message to other nodes in the Diameter network. 13.The system of claim 11 wherein using the error indication information toupdate the status information includes updating status informationmaintained by each of a plurality of message processors of the DSR. 14.A system for providing answer message-based network management, thesystem comprising: a Diameter signaling router including: a Diametermessage processor associated for receiving a first Diameter answermessage from a first Diameter node, wherein the first Diameter answermessage includes error indicator information; and a network management(NM) module for examining the error indicator information contained inthe first Diameter answer message and using the error indicatorinformation to update status information for routes maintained by theDSR to the first Diameter node, wherein the error indicator informationindicates that the first answer message cannot be immediately deliveredto a peer because a transport layer queue for the peer is full orcongested.
 15. The system of claim 14 wherein the network managementmodule is configured to buffer the first answer message for aconfigurable time period X1.
 16. The system of claim 15 wherein thenetwork management module is configured to forward the buffered answermessage to the peer if the peer's status changes before the configurabletime period X1 expires.
 17. The system of claim 15 wherein the networkmanagement module is configured to attempt to forward the bufferedanswer message, if the configurable time period X1 expires and thepeer's status is available, until the buffer is flushed or anotherblocking condition occurs.
 18. The system of claim 14 wherein thenetwork management module is configured to establish a maximum answermessage queue delay time period after expiration of which the answermessage will be discarded.
 19. A system for providing answermessage-based network management, the system comprising: a Diametersignaling router including: a Diameter message processor associated forreceiving a first Diameter answer message from a first Diameter node,wherein the first Diameter answer message includes error indicatorinformation; and a network management (NM) module for examining theerror indicator information contained in the first Diameter answermessage and using the error indicator information to update statusinformation for routes maintained by the DSR to the first Diameter node,wherein the network management module is configured for: generating asecond answer message on behalf of the first Diameter node in responseto receiving the first Diameter request message, wherein the secondanswer message includes information based on at least a portion of theerror indicator information included in the first Diameter answermessage; and communicating the second Diameter answer message to thesecond Diameter node.
 20. The system of claim 19 wherein the cachingmodule is configured to identify an affected application subsystemassociated with a Diameter node.
 21. A non-transitory computer readablemedium comprising computer executable instructions embodied in anon-transitory computer readable medium and when executed by a processorof a computer performs steps comprising: at a Diameter signaling router(DSR): receiving, a Diameter answer message from a first Diameter node,wherein the Diameter answer message includes error indicatorinformation, wherein the first Diameter answer message is transmitted bythe first Diameter node in response to a request transmitted to thefirst Diameter node and wherein the error indicator information concernsstatus of the first Diameter node; examining the error indicatorinformation included in the Diameter message; and using the errorindicator information to update status information for routes to thefirst Diameter node.